missing rectangular area where mark can be set on default theme

Description

When porting ChocolateCastle and LibMaker, found that on default theme there is missing rectangular areaa where marks can be set, and instead it looks like its just whole background.

I attached 2 images to show what i mean. One are ChocolateCastle without mark set and with mark set and another one LibMaker with the same empty and set marks. I also point out on problem areas via red rectangle.

You are right. The image is visible only because it heavily relies on that specific theme. A different theme will definitely cause exactly the same invisible unchecked Checkmark object.

You can see for yourself that the checkmark image is always visible in the lower part of your LibMaker screenshot. Just look at the checkmark objects label "Every functions in a separate file" and "Every class method in a separate file".